Multilayer capacitor with (1) an element body having internal electrodes and (2) opposing terminal electrodes

ABSTRACT

A length in a first direction of the element body is smaller than a length in a second direction of the element body and smaller than a length in a third direction of the element body, the second direction being perpendicular to the first direction, the third direction being perpendicular to the first and second direction. Each of a first terminal electrode and a second terminal electrode includes a sintered conductor layer formed on the element body, a first plated layer formed on the sintered conductor layer, and a second plated layer formed on the first plated layer. In each of a first electrode portion disposed on a principal face and a third electrode portion disposed on a principal face, a maximum thickness of the sintered conductor layer is larger than a thickness of the first plated layer and not more than a thickness of the second plated layer.

TECHNICAL FIELD

The present invention relates to a multilayer capacitor.

BACKGROUND

Known multilayer capacitor described in Japanese Unexamined Patent Publication No. 2010-129737 are multilayer capacitors that are built into substrates with built-in electronic components. The multilayer capacitor includes an element body of a rectangular parallelepiped shape, a plurality of first internal electrodes, a plurality of second internal electrodes, a first terminal electrode, and a second terminal electrode. The plurality of first and second internal electrodes are alternately disposed in the element body to oppose each other. The first terminal electrode is disposed on the element body and is connected to the plurality of first internal electrodes. The second terminal electrode is disposed on the element body and is connected to the plurality of second internal electrodes.

SUMMARY

In a process of manufacturing the substrate with built-in electronic component, the multilayer capacitor is built into the substrate and thereafter via holes are formed in the substrate to reach the first terminal electrode and the second terminal electrode. The via holes are formed by laser processing. In this case, the first terminal electrode and the second terminal electrode are irradiated with a laser beam, and may be damaged by the laser beam.

One aspect of the present invention provides a multilayer capacitor which is feasible to suppress the effect of damage due to the irradiation with the laser beam and achieves reduction in height.

A multilayer capacitor according to one aspect of the present invention includes an element body of a rectangular parallelepiped shape, a plurality of first internal electrodes, a plurality of second internal electrodes, a first terminal electrode, and a second terminal electrode. The element body includes a pair of principal surfaces opposing each other in a first direction, a pair of first side surfaces opposing each other in a second direction perpendicular to the first direction, and a pair of second side surfaces opposing each other in a third direction perpendicular to the first and second directions. The plurality of first internal electrodes and the plurality of second internal electrodes are alternately disposed in the element body to oppose each other in the first direction. The first terminal electrode includes a first electrode portion disposed on the principal surface and a second electrode portion disposed on one of the first side surfaces. The second electrode portion is connected to the plurality of first internal electrodes. The second terminal electrode includes a third electrode portion disposed on the principal surface and a fourth electrode portion disposed on the other of the first side surfaces. The third electrode portion is separated from the first electrode portion in the second direction on the principal surface. The fourth electrode portion is connected to the plurality of second internal electrodes. The element body includes an inner layer portion and a pair of outer layer portions. The inner layer portion is located between the pair of outer layer portions in the first direction. The plurality of first internal electrodes and the plurality of second internal electrodes are located in the inner layer portion. A length in the first direction of the element body is smaller than a length in the second direction of the element body and smaller than a length in the third direction of the element body. Each of the first terminal electrode and the second terminal electrode includes a sintered conductor layer formed on the element body, a first plated layer formed on the sintered conductor layer, and a second plated layer formed on the first plated layer. In each of the first electrode portion and the third electrode portion, a maximum thickness of the sintered conductor layer is larger than a thickness of the first plated layer and not more than a thickness of the second plated layer.

In the multilayer capacitor according to the one aspect, the length in the first direction of the element body is smaller than the length in the second direction of the element body and smaller than the length in the third direction of the element body. For this reason, the multilayer capacitor is obtained that has reduced height and the multilayer capacitor is realized that is suitable for built-in mounting in a substrate. The first terminal electrode includes the first electrode portion disposed on the principal surface of the element body and the second terminal electrode includes the third electrode portion disposed on the principal surface of the element body. The multilayer capacitor according to the one aspect can be electrically connected to wiring formed on the substrate, on the foregoing principal surface side of the element body. Therefore, the multilayer capacitor according to the one aspect can be readily built into the substrate.

In each of the first electrode portion and the third electrode portion, the maximum thickness of the sintered conductor layer is larger than the thickness of the first plated layer. For this reason, the first plated layer is thin in the multilayer capacitor according to the one aspect, compared to a multilayer capacitor in which in each of the first electrode portion and the third electrode portion, the thickness of the first plated layer is not less than the maximum thickness of the sintered conductor layer. In the multilayer capacitor according to the one aspect, therefore, it is feasible to reduce stress occurring in a process of forming the first plated layer on the sintered conductor layer. In the multilayer capacitor according to the one aspect, the second plated layer is thick, compared to a multilayer capacitor in which in each of the first electrode portion and the third electrode portion, the thickness of the second plated layer is smaller than the maximum thickness of the sintered conductor layer. Therefore, it is feasible to suppress the effect of damage due to the irradiation with the laser beam even in the case where the first and third electrode portions are irradiated with the laser beam.

The sintered conductor layer may contain Cu or Ni. In this case, the first internal electrodes and the first terminal electrode are securely kept in contact with each other due to the first internal electrodes being connected to the sintered conductor layer of the first terminal electrode. The second internal electrodes and the second terminal electrode are securely kept in contact with each other due to the second internal electrodes being connected to the sintered conductor layer of the second terminal electrode.

The first plated layer may contain Ni or Sn. In this case, the first plated layer restrains the sintered conductor layer from being damaged in a process of forming the second plated layer. For this reason, in the multilayer capacitor of this embodiment, it is feasible to suppress degradation of insulation resistance of the multilayer capacitor.

The second plated layer may contain Cu or Au. In this case, it is feasible to ensure connectivity between the wiring formed on the substrate and the first and second terminal electrodes.

A difference between a maximum thickness and a minimum thickness of the first electrode portion may be smaller than a difference between a maximum thickness and a minimum thickness of the second electrode portion, and a difference between a maximum thickness and a minimum thickness of the third electrode portion may be smaller than a difference between a maximum thickness and a minimum thickness of the fourth electrode portion. In this case, the first electrode portion has a higher degree of flatness than the second electrode portion does. The third electrode portion has a higher degree of flatness than the fourth electrode portion does. These configurations improve connection reliability between the wiring formed on the substrate and the first and second terminal electrodes.

Thicknesses of the respective outer layer portions may be smaller than the maximum thickness of the first electrode portion and smaller than the maximum thickness of the third electrode portion. In this case, it is feasible to further suppress the effect of damage due to the irradiation with the laser beam and achieve further reduction in height of the multilayer capacitor.

The length in the first direction of the element body may be smaller than a length in the second direction of the first electrode portion and smaller than a length in the second direction of the third electrode portion. In this case, it is feasible to achieve further reduction in height of the multilayer capacitor. In the multilayer capacitor of this embodiment, the areas of the first and third electrode portions are larger and thus electrode areas to be connected to the wiring formed on the substrate are large, compared to a multilayer capacitor in which the length in the second direction of the first electrode portion and the length in the second direction of the third electrode portion are smaller than the length in the first direction of the element body. For this reason, it is easy to implement connection between the wiring formed on the substrate and the first and second terminal electrodes.

The length in the first direction of the element body may be smaller than a gap between the first electrode portion and the third electrode portion in the second direction. In this case, it is also feasible to achieve further reduction in height of the multilayer capacitor.

A gap between the first electrode portion and the third electrode portion in the second direction may be not more than a length in the second direction of the first electrode portion and not more than a length in the second direction of the third electrode portion. In the multilayer capacitor of this embodiment, the areas of the first and third electrode portions are larger and thus electrode areas to be connected to the wiring formed on the substrate are large, compared to a multilayer capacitor in which the gap between the first electrode portion and the third electrode portion in the second direction is larger than the length in the second direction of the first electrode portion and larger than the length in the second direction of the third electrode portion. For this reason, it is easy to implement connection between the wiring forming on the substrate and the first and second terminal electrodes.

The thicknesses of the respective outer layer portions may be smaller than the thickness of the second plated layer. In this case, it is feasible to further suppress the effect of damage due to the irradiation with the laser beam and achieve further reduction in height of the multilayer capacitor.

The second plated layer may be a Cu-plated layer, and projections being made of Cu may be formed on a surface of the Cu-plated layer. The multilayer capacitor is placed in a housing portion of a substrate and thereafter the housing portion is filled with a resin, whereby the multilayer capacitor is built into the substrate. When the projections are formed on the second plated layer, the projections form unevenness on the surface of the second plated layer. The configuration whereby the projections are formed on the second plated layer provides the second plated layer with a large surface area and better engagement between the second plated layer and resin due to the unevenness, compared to a configuration without the projections. Therefore, adhesion between the second plated layer and resin can be improved when the multilayer capacitor is built into the substrate.

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not to be considered as limiting the present invention.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a multilayer capacitor according to an embodiment.

FIG. 2 is a plan view showing the multilayer capacitor according to the embodiment.

FIG. 3 is a side view showing the multilayer capacitor according to the embodiment.

FIG. 4 is a drawing for explaining a cross-sectional configuration along the line IV-IV in FIG. 2.

FIG. 5 is a drawing for explaining a cross-sectional configuration along the line V-V in FIG. 2.

FIG. 6 is a drawing for explaining a cross-sectional configuration along the line VI-VI in FIG. 2.

FIG. 7A is a plan view showing a first internal electrode and FIG. 7B a plan view showing a second internal electrode.

FIG. 8 is a perspective view showing a multilayer capacitor according to a modification example of the embodiment.

FIG. 9 is a perspective view showing a third electrode layer.

FIG. 10 is a drawing for explaining a cross-sectional configuration of a first terminal electrode.

FIG. 11 is a drawing for explaining a cross-sectional configuration of a second terminal electrode.

FIG. 12 is a drawing for explaining a mounted structure of the multilayer capacitor according to the embodiment.

FIG. 13 is a perspective view showing a multilayer capacitor according to a modification example of the embodiment.

FIG. 14 is a drawing for explaining a cross-sectional configuration of the multilayer capacitor according to the modification example of the embodiment.

FIG. 15 is a drawing for explaining a cross-sectional configuration of the multilayer capacitor according to the modification example of the embodiment.

FIG. 16 is a drawing for explaining a cross-sectional configuration of the multilayer capacitor according to the modification example of the embodiment.

DETAILED DESCRIPTION

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description, the same elements or elements with the same functionality will be denoted by the same reference signs, without redundant description.

A configuration of a multilayer capacitor C1 according to the present embodiment will be described with reference to FIGS. 1 to 6. FIG. 1 is a perspective view showing the multilayer capacitor according to the present embodiment. FIG. 2 is a plan view showing the multilayer capacitor according to the present embodiment. FIG. 3 is a side view showing the multilayer capacitor according to the present embodiment. FIG. 4 is a drawing for explaining a cross-sectional configuration along the line IV-IV in FIG. 2. FIG. 5 is a drawing for explaining a cross-sectional configuration along the line V-V in FIG. 2. FIG. 6 is a drawing for explaining a cross-sectional configuration along the line VI-VI in FIG. 2.

The multilayer capacitor C1, as shown in FIGS. 1 to 6, includes an element body 2 of a rectangular parallelepiped shape, and, a first terminal electrode 5 and a second terminal electrode 7 disposed on the exterior surface of the element body 2. The first terminal electrode 5 and second terminal electrode 7 are separated from each other. The rectangular parallelepiped shape embraces a shape of a rectangular parallelepiped with chamfered corners and ridgelines, and a shape of a rectangular parallelepiped with rounded corners and ridgelines.

The element body 2 includes, as the outer surface, a pair of principal surfaces 2 a, 2 b of a substantially rectangular shape opposing each other, a pair of first side surfaces 2 c, 2 d opposing each other, and a pair of second side surfaces 2 e, 2 f opposing each other. A direction in which the pair of principal surfaces 2 a, 2 b oppose is a first direction D1, a direction in which the pair of first side surfaces 2 c, 2 d oppose is a second direction D2, and a direction in which the pair of second side surfaces 2 e, 2 f oppose is a third direction D3. In the present embodiment, the first direction D1 is a height direction of the element body 2. The second direction D2 is a width direction of the element body 2 and is perpendicular to the first direction D1. The third direction D3 is the longitudinal direction of the element body 2 and is perpendicular to the first direction D1 and to the second direction D2.

The length in the first direction D1 of the element body 2 is smaller than the length in the third direction D3 of the element body 2 and smaller than the length in the second direction D2 of the element body 2. The length in the second direction D2 of the element body 2 is larger than the length in the third direction D3 of the element body 2. The length in the third direction D3 of the element body 2 is, for example, from 0.2 to 0.8 mm. The length in the second direction D2 of the element body 2 is, for example, from 0.4 to 1.6 mm. The length in the first direction D1 of the element body 2 is, for example, from 0.1 to 0.35 mm. The multilayer capacitor C1 is an ultra-low-profile multilayer capacitor. The length in the second direction D2 of the element body 2 may be equivalent to the length in the third direction D3 of the element body 2. The length in the third direction D3 of the element body 2 may be larger than the length in the second direction D2 of the element body 2.

It is noted herein that the term “equivalent” does not always mean that values are exactly equal. The values may also be said to be equivalent in cases where the values have a slight difference within a predetermined range or include a manufacturing error or the like. For example, when a plurality of values fall within the range of ±5% of an average of the plurality of values, the plurality of values may be defined as equivalent.

The pair of first side surfaces 2 c, 2 d extend in the first direction D1 to connect the pair of principal surfaces 2 a, 2 b. The pair of first side surfaces 2 c, 2 d also extend in the third direction D3 (the long-side direction of the pair of principal surfaces 2 a, 2 b). The pair of second side surfaces 2 e, 2 f extend in the first direction D1 to connect the pair of principal surfaces 2 a, 2 b. The pair of second side surfaces 2 e, 2 f also extend in the second direction D2 (the short-side direction of the pair of principal surfaces 2 a, 2 b).

The element body 2 is constituted of a plurality of dielectric layers stacked in the direction in which the pair of principal surfaces 2 a, 2 b oppose (the first direction D1). In the element body 2, the direction in which the plurality of dielectric layers are stacked coincides with the first direction D1. For example, each dielectric layer includes a sintered body of a ceramic green sheet containing a dielectric material (BaTiO₃-based, Ba(Ti, Zr)O₃-based, (Ba, Ca)TiO₃-based, or other dielectric ceramic). In the element body 2 in practice, the dielectric layers are so integrated that no boundary can be visually recognized between the dielectric layers.

The multilayer capacitor C1, as shown in FIGS. 4 to 6, includes a plurality of first internal electrodes 11 and a plurality of second internal electrodes 13. The first and second internal electrodes 11, 13 contain an electroconductive material (e.g., Ni or Cu or the like) that is commonly used as internal electrodes of multilayer electric elements. Each of the first and second internal electrodes 11, 13 includes a sintered body of an electroconductive paste containing the foregoing electroconductive material.

The first internal electrodes 11 and the second internal electrodes 13 are disposed at different positions (layers) in the first direction D1. The first internal electrodes 11 and the second internal electrodes 13 are alternately disposed to oppose with a space in between in the first direction D1, in the element body 2. The first internal electrodes 11 and the second internal electrodes 13 have respective polarities different from each other.

Each first internal electrode 11, as shown in FIG. 7A, includes a main electrode portion 11 a and a connection portion 11 b. The connection portion 11 b extends from one side (one short side) of the main electrode portion 11 a and is exposed at the first side surface 2 c. The first internal electrode 11 is exposed at the first side surface 2 c but not exposed at the pair of principal surfaces 2 a, 2 b, the first side surface 2 d, and the pair of second side surfaces 2 e, 2 f. The main electrode portion 11 a and the connection portion 11 b are integrally formed.

The main electrode portion 11 a is of a rectangular shape with the long sides along the second direction D2 and the short sides along the third direction D3. In the main electrode portion 11 a of each first internal electrode 11, the length thereof in the second direction D2 is larger than the length thereof in the third direction D3. The connection portion 11 b extends from the end on the first side surface 2 c side of the main electrode portion 11 a to the first side surface 2 c. The length in the second direction D2 of the connection portion 11 b is smaller than the length in the second direction D2 of the main electrode portion 11 a. The length in the third direction D3 of the connection portion 11 b is equivalent to the length in the third direction D3 of the main electrode portion 11 a. The connection portion 11 b is connected at its end exposed at the first side surface 2 c, to the first terminal electrode 5. The length in the third direction D3 of the connection portion 11 b may be smaller than the length in the third direction D3 of the main electrode portion 11 a.

Each second internal electrode 13, as shown in FIG. 7B, includes a main electrode portion 13 a and a connection portion 13 b. The main electrode portion 13 a opposes the main electrode portion 11 a through a part (dielectric layer) of the element body 2 in the first direction D1. The connection portion 13 b extends from one side (one short side) of the main electrode portion 13 a and is exposed at the first side surface 2 d. The second internal electrode 13 is exposed at the first side surface 2 d but not exposed at the pair of principal surfaces 2 a, 2 b, the first side surface 2 c, and the pair of second side surfaces 2 e, 2 f. The main electrode portion 13 a and the connection portion 13 b are integrally formed.

The main electrode portion 13 a is of a rectangular shape with the long sides along the second direction D2 and the short sides along the third direction D3. In the main electrode portion 13 a of each second internal electrode 13, the length thereof in the second direction D2 is larger than the length thereof in the third direction D3. The connection portion 13 b extends from the end on the first side surface 2 d side of the main electrode portion 13 a to the first side surface 2 d. The length in the second direction D2 of the connection portion 13 b is smaller than the length in the second direction D2 of the main electrode portion 13 a. The length in the third direction D3 of the connection portion 13 b is equivalent to the length in the third direction D3 of the main electrode portion 13 a. The connection portion 13 b is connected at its end exposed at the first side surface 2 d, to the second terminal electrode 7. The length in the third direction D3 of the connection portion 13 b may be smaller than the length in the third direction D3 of the main electrode portion 13 a.

The element body 2, as shown in FIGS. 4 to 6, includes an inner layer portion 3A and a pair of outer layer portions 3B, 3C. The plurality of first internal electrodes 11 and the plurality of second internal electrodes 13 are located in the inner layer portion 3A. The pair of outer layer portions 3B, 3C are located between the pair of outer layer portions 3B, 3C in the first direction D1. The first internal electrodes 11 and second internal electrodes 13 are not located in the pair of outer layer portions 3B, 3C.

The thickness T_(3B) in the first direction D1 of the outer layer portion 3B is defined by a gap in the first direction D1 between the principal surface 2 a and the internal electrode closest to the principal surface 2 a (the first internal electrode 11 in the present embodiment). The thickness T_(3C) in the first direction D1 of the outer layer portion 3C is defined by a gap in the first direction D1 between the principal surface 2 b and the internal electrode closest to the principal surface 2 b (the second internal electrode 13 in the present embodiment). The thickness T_(3A) in the first direction D1 of the inner layer portion 3A is defined by a gap in the first direction D1 between the internal electrode closest to the principal surface 2 a and the internal electrode closest to the principal surface 2 b. A total value of the thickness T_(3A) of the inner layer portion 3A, the thickness T_(3B) of the outer layer portion 3B, and the thickness T_(3C) of the outer layer portion 3C is equal to the length in the first direction D1 of the element body 2. The thicknesses T_(3B), T_(3C) of the respective outer layer portions 3B, 3C are smaller than the thickness T_(3A) of the inner layer portion 3A.

The first terminal electrode 5 is located at the end on the first side surface 2 c side of the element body 2 when viewed along the second direction D2. The first terminal electrode 5 includes an electrode portion 5 a disposed on the principal surface 2 a, an electrode portion 5 b disposed on the principal surface 2 b, an electrode portion 5 c disposed on the first side surface 2 c, and electrode portions 5 d disposed on the pair of second side surfaces 2 e, 2 f. The first terminal electrode 5 is formed on the five surfaces 2 a, 2 b, 2 c, 2 e, and 2 f. The electrode portions 5 a, 5 b, 5 c, 5 d adjacent to each other are connected to each other at the ridgelines of the element body 2 to be electrically connected to each other.

The electrode portion 5 a and the electrode portion 5 c are connected at the ridgeline between the principal surface 2 a and the first side surface 2 c. The electrode portion 5 a and the electrode portions 5 d are connected at the ridgelines between the principal surface 2 a and each of the second side surfaces 2 e, 2 f. The electrode portion 5 b and the electrode portion 5 c are connected at the ridgeline between the principal surface 2 b and the first side surface 2 c. The electrode portion 5 b and the electrode portions 5 d are connected at the ridgelines between the principal surface 2 b and each of the second side surfaces 2 e, 2 f. The electrode portion 5 c and the electrode portions 5 d are connected at the ridgelines between the first side surface 2 c and each of the second side surfaces 2 e, 2 f.

The electrode portion 5 c is disposed to cover all exposed portions of the respective connection portions 11 b on the first side surface 2 c, Each connection portion 11 b is directly connected to the first terminal electrode 5. The connection portion 11 b connects the main electrode portion 11 a and the electrode portion 5 c. Each first internal electrode 11 is electrically connected to the first terminal electrode 5.

The second terminal electrode 7 is located at the end on the first side surface 2 d side of the element body 2 when viewed along the second direction D2. The second terminal electrode 7 includes an electrode portion 7 a disposed on the principal surface 2 a, an electrode portion 7 b disposed on the principal surface 2 b, an electrode portion 7 c disposed on the first side surface 2 d, and electrode portions 7 d disposed on the pair of second side surfaces 2 e, 2 f. The second terminal electrode 7 is formed on the five surfaces 2 a, 2 b, 2 d, 2 e, and 2 f. The electrode portions 7 a, 7 b, 7 c, 7 d adjacent to each other are connected to each other at the ridgelines of the element body 2 to be electrically connected to each other.

The electrode portion 7 a and the electrode portion 7 c are connected at the ridgeline between the principal surface 2 a and the first side surface 2 d. The electrode portion 7 a and the electrode portions 7 d are connected at the ridgelines between the principal surface 2 a and each of the second side surfaces 2 e, 2 f. The electrode portion 7 b and the electrode portion 7 c are connected at the ridgeline between the principal surface 2 b and the first side surface 2 d. The electrode portion 7 b and the electrode portions 7 d are connected at the ridgelines between the principal surface 2 b and each of the second side surfaces 2 e, 2 f. The electrode portion 7 c and the electrode portions 7 d are connected at the ridgelines between the first side surface 2 d and each of the second side surfaces 2 e, 2 f.

The electrode portion 7 c is disposed to cover all exposed portions of the respective connection portions 13 b on the first side surface 2 d. Each connection portion 13 b is directly connected to the second terminal electrode 7. The connection portion 13 b connects the main electrode portion 13 a and the electrode portion 7 c. Each second internal electrode 13 is electrically connected to the second terminal electrode 7.

The first terminal electrode 5 and the second terminal electrode 7 are separated in the second direction D2. The electrode portion 5 a and the electrode portion 7 a disposed on the principal surface 2 a are separated in the second direction D2 on the principal surface 2 a. The electrode portion 5 b and the electrode portion 7 b disposed on the principal surface 2 b are separated in the second direction D2 on the principal surface 2 b. The electrode portion 5 d and the electrode portion 7 d disposed on the second side surface 2 e are separated in the second direction D2 on the second side surface 2 e. The electrode portion 5 d and the electrode portion 7 d disposed on the second side surface 2 f are separated in the second direction D2 on the second side surface 2 f.

The length L₅₁ in the second direction D2 of the electrode portions 5 a, 5 b and the length L₇₁ in the second direction D2 of the electrode portions 7 a, 7 b are equivalent. A gap G₁ in the second direction D2 between the electrode portions 5 a, 5 b and the electrode portions 7 a, 7 b is not more than the length L₅₁ and not more than the length L₇₁. In the present embodiment, the gap G₁ is smaller than each of the lengths L₅₁, L₇₁.

Each of the first and second terminal electrodes 5, 7 includes a first electrode layer 21, a second electrode layer 23, and a third electrode layer 25. Each of the electrode portions 5 a, 5 b, 5 c, 5 d and the electrode portions 7 a, 7 b, 7 c, 7 d includes the first electrode layer 21, second electrode layer 23, and third electrode layer 25. The third electrode layer 25 constitutes the outermost layer of each of the first and second terminal electrodes 5, 7.

The first electrode layer 21 is formed by applying an electroconductive paste onto the surface of the element body 2 and sintering it. The first electrode layer 21 is a sintered conductor layer (sintered metal layer). In the present embodiment, the first electrode layer 21 is a sintered conductor layer made of Cu. The first electrode layer 21 may be a sintered conductor layer made of Ni. The first electrode layer 21 contains Cu or Ni. For example, the electroconductive paste is obtained by mixing a powder made of Cu or Ni, a glass component, an organic binder, and an organic solvent. The thickness of the first electrode layer 21 is, for example, 20 μm at a maximum and 5 μm at a minimum.

The second electrode layer 23 is formed by plating on the first electrode layer 21. In the present embodiment, the second electrode layer 23 is an Ni-plated layer formed by Ni plating on the first electrode layer 21. The second electrode layer 23 may be an Sn-plated layer. The second electrode layer 23 contains Ni or Sn. The thickness of the second electrode layer 23 is, for example, from 1 to 5 μm.

The third electrode layer 25 is formed by plating on the second electrode layer 23. In the present embodiment, the third electrode layer 25 is a Cu-plated layer formed by Cu plating on the second electrode layer 23. The third electrode layer 25 may be an Au-plated layer. The third electrode layer 25 contains Cu or Au. The thickness of the third electrode layer 25 is, for example, from 1 to 15 μm.

A plurality of projections 25 a may be formed on the surface of the third electrode layer 25 being the Cu-plated layer, as also shown in FIGS. 8 and 9. In this case, each projection 25 a is made of Cu. A diameter of each projection 25 a is from 10 to 30 μm and a height of each projection 25 a from 1 to 10 μm.

Next, the thicknesses of the respective electrode portions 5 a, 5 b, 5 c, 7 a, 7 b, 7 c of the first and second terminal electrodes 5, 7 will be described with reference to FIGS. 10 and 11.

As shown in FIG. 10, the thicknesses of the first electrode layer 21 of each of the electrode portions 5 a, 5 b are determined in such a manner that the maximum thickness is the thickness of a central portion as viewed from the first direction D1 and that the minimum thickness is the thickness of a portion located at the ridgeline between the principal surface 2 a or 2 b and the first side surface 2 c. The thicknesses of the first electrode layer 21 of the electrode portion 5 c are determined in such a manner that the maximum thickness is the thickness of a central portion as viewed from the second direction D2 and that the minimum thickness is the thickness of each of portions located at the ridgelines between the principal surfaces 2 a, 2 b and the first side surface 2 c. The electrode portions 5 a, 5 b and the electrode portion 5 c are connected at the ridgelines between the principal surfaces 2 a, 2 b and the first side surface 2 c. For this reason, the thicknesses of the portions located at the ridgelines in the first electrode layers 21 of the electrode portions 5 a, 5 b are equivalent to the thicknesses of the portions located at the ridgelines in the first electrode layer 21 of the electrode portion 5 c.

The first electrode layer 21 of each electrode portion 5 a or 5 b has the maximum thickness T_(5S1) and the minimum thickness T_(5Smin). The first electrode layer 21 of the electrode portion 5 c has the maximum thickness T_(5S2) and the minimum thickness T_(5Smin). The second electrode layer 23 has the thickness T_(5P1) equivalent throughout all of the electrode portions 5 a, 5 b, 5 c, The third electrode layer 25 also has the thickness T_(5P2) equivalent throughout all of the electrode portions 5 a, 5 b, 5 c.

The thickness of each electrode portion 5 a, 5 b, or 5 c is defined by a total value of the respective thicknesses of the first electrode layer 21, the second electrode layer 23, and the third electrode layer 25 constituting the corresponding electrode portion 5 a, 5 b, or 5 c. Therefore, each electrode portion 5 a or 5 b has the maximum thickness (T_(5S1)+T_(5P1)+T_(5P2)) in the central portion as viewed from the first direction D1. Each electrode portion 5 a or 5 b has the minimum thickness (T_(5Smin)+T_(5P1)+T_(5P2)) in the portion located at the ridgeline between the principal surface 2 a or 2 b and the first side surface 2 c, The electrode portion 5 c has the maximum thickness (T_(5S2)+T_(5P1)+T_(5P2)) in the central portion as viewed from the second direction D2. The electrode portion 5 c has the minimum thickness (T_(5Smin)+T_(5P1)+T_(5P2)) in the portions located at the ridgelines between the principal surfaces 2 a, 2 b and the first side surface 2 c.

As shown in FIG. 11, the thicknesses of the first electrode layer 21 of each of the electrode portions 7 a, 7 b are determined in such a manner that the maximum thickness is the thickness of a central portion as viewed from the first direction D1 and that the minimum thickness is the thickness of a portion located at the ridgeline between the principal surface 2 a or 2 b and the first side surface 2 d. The thicknesses of the first electrode layer 21 of the electrode portion 7 c are determined in such a manner that the maximum thickness is the thickness of a central portion as viewed from the second direction D2 and that the minimum thickness is the thickness of each of portions located at the ridgelines between the principal surfaces 2 a, 2 b and the first side surface 2 d. The electrode portions 7 a, 7 b and the electrode portion 7 c are connected at the ridgelines between the principal surfaces 2 a, 2 b and the first side surface 2 d. For this reason, the thicknesses of the portions located at the ridgelines in the first electrode layers 21 of the electrode portions 7 a, 7 b are equivalent to the thicknesses of the portions located at the ridgelines in the first electrode layer 21 of the electrode portion 7 c.

The first electrode layer 21 of each electrode portion 7 a or 7 b has the maximum thickness T_(7S1) and the minimum thickness T_(7Smin). The first electrode layer 21 of the electrode portion 7 c has the maximum thickness T_(7S2) and the minimum thickness T_(7Smin). The second electrode layer 23 has the thickness T_(7P1) equivalent throughout all of the electrode portions 7 a, 7 b, 7 c. The third electrode layer 25 also has the thickness T_(7P2) equivalent throughout all of the electrode portions 7 a, 7 b, 7 c.

The thickness of each electrode portion 7 a, 7 b, or 7 c is defined by a total value of the respective thicknesses of the first electrode layer 21, the second electrode layer 23, and the third electrode layer 25 constituting the corresponding electrode portion 7 a, 7 b, or 7 c. Therefore, each electrode portion 7 a or 7 b has the maximum thickness (T_(7S1)+T_(7P1)+T_(7P2)) in the central portion as viewed from the first direction D1. Each electrode portion 7 a or 7 b has the minimum thickness (T_(7Smin)+T_(7P1)+T_(7P2)) in the portion located at the ridgeline between the principal surface 2 a or 2 b and the first side surface 2 d. The electrode portion 7 c has the maximum thickness (T_(7S2)+T_(7P1)+T_(7P2)) in the central portion as viewed from the second direction D2. The electrode portion 7 c has the minimum thickness (T_(7Smin)+T_(7P1)+T_(7P2)) in the portions located at the ridgelines between the principal surfaces 2 a, 2 b and the first side surface 2 d.

A difference between the maximum thickness T_(5S1) and the minimum thickness T_(5Smin) of the first electrode layer 21 of each of the electrode portions 5 a, 5 b is smaller than a difference between the maximum thickness T_(5S2) and the minimum thickness T_(5Smin) of the first electrode layer 21 of the electrode portion 5 c. A difference between the maximum thickness (T_(5S1)+T_(5P1)+T_(5P2)) and the minimum thickness (T_(5Smin)+T_(5P1)+T_(5P2)) of each electrode portion 5 a or 5 b is smaller than a difference between the maximum thickness (T_(5S2)+T_(5P1)+T_(5P2)) and the minimum thickness (T_(5Smim)+T_(5P1)+T_(5P2)) of the electrode portion 5 c.

A difference between the maximum thickness T_(7S1) and the minimum thickness T_(7Smin) of the first electrode layer 21 of each of the electrode portions 7 a, 7 b is smaller than a difference between the maximum thickness T_(7S2) and the minimum thickness T_(7Smin) of the first electrode layer 21 of the electrode portion 7 c. A difference between the maximum thickness (T_(7S1)+T_(7P1)+T_(7P2)) and the minimum thickness (T_(7Smin)+T_(7P1)+T_(7P2)) of each electrode portion 7 a or 7 b is smaller than a difference between the maximum thickness (T_(7S2)+T_(7P1)+T_(7P2)) and the minimum thickness (T_(7Smin)+T_(7P1)+T_(7P2)) of the electrode portion 7 c.

In each of the electrode portions 5 a, 5 b, the maximum thickness T_(5S1) of the first electrode layer 21 is larger than the thickness T_(5P1) of the second electrode layer 23 and not more than the thickness T_(5P2) of the third electrode layer 25. In each of the electrode portions 7 a, 7 b, the maximum thickness T_(7S1) of the first electrode layer 21 is larger than the thickness T_(7P1) of the second electrode layer 23 and not more than the thickness T_(7P2) of the third electrode layer 25.

In the present embodiment, the maximum thickness T_(5S1) and the maximum thickness T_(7S1) are equivalent. Each of the maximum thicknesses T_(5S1), T_(7S1) is, for example, 8 μm. The maximum thickness T_(5S2) and the maximum thickness T_(7S2) are equivalent. Each of the maximum thicknesses T_(5S2), T_(7S2) is, for example, 12 μm. The minimum thickness T_(5Smin) and the minimum thickness T_(7Smin) are equivalent. Each of the minimum thickness T_(5Smin) and the minimum thickness T_(7Smin) is, for example, 1 μm. The thickness T_(5P1) and the thickness T_(7P1) are equivalent. Each of the thicknesses T_(5P1), T_(7P1) is, for example, 3 μm. The thickness T_(5P2) and the thickness T_(7P2) are equivalent. Each of the thicknesses T_(5P2), T_(7P2) is, for example, 10 μm.

The maximum thickness (T_(5S1)+T_(5P1)+T_(5P2)) of each electrode portion 5 a or 5 b and the maximum thickness (T_(7S1)+T_(7P1)+T_(7P2)) of each electrode portion 7 a or 7 b are larger than the thicknesses T_(3B), T_(3C) of the respective outer layer portions 3B, 3C. Each of the thicknesses T_(3B), T_(3C) is, for example, 15 μm.

In the present embodiment, as described above, the length in the first direction D1 of the element body 2 is smaller than the length in the second direction D2 of the element body 2 and smaller than the length in the third direction D3 of the element body 2. For this reason, the multilayer capacitor C1 is obtained that has reduced height and the multilayer capacitor is realized that is suitable for built-in mounting in a substrate. The first terminal electrode 5 includes the electrode portions 5 a, 5 b disposed on the principal surfaces 2 a, 2 b and the second terminal electrode 7 includes s the electrode portions 7 a, 7 b disposed on the principal surfaces 2 a, 2 b. The multilayer capacitor C1 can be electrically connected to wiring formed on the substrate, on the principal surface 2 a side of the element body 2, on the principal surface 2 b side of the element body 2, or, on both of the principal surface 2 a, 2 b sides of the element body 2. Therefore, the multilayer capacitor C1 can be readily built into the substrate.

In the electrode portions 5 a, 5 b, 7 a, 7 b, the maximum thicknesses T_(5S1), T_(7S1) of the first electrode layers 21 are larger than the thicknesses T_(5P1), T_(7P1) of the second electrode layers 23. For this reason, the second electrode layers 23 are thin and it is thus feasible to reduce stress occurring in a process of forming the second electrode layers 23 on the first electrode layers 21 in the multilayer capacitor C1, compared to a multilayer capacitor in which the thicknesses T_(5P1), T_(7P1) of the second electrode layers 23 are not less than the maximum thicknesses T_(5S1), T_(7S1) of the first electrode layers 21.

After the multilayer capacitor C1 is built into the substrate, via holes are formed in the substrate to reach the first and second terminal electrodes 5, 7 (electrode portions 5 a, 5 b, 7 a, 7 b). The via holes are formed by laser processing. In this case, the electrode portions 5 a, 5 b, 7 a, 7 b are irradiated with a laser beam, and may be damaged by the laser beam.

In the electrode portions 5 a, 5 b, 7 a, 7 b, the maximum thicknesses T_(5S1), T_(7S1) of the first electrode layers 21 are not more than the thicknesses T_(5P2), T_(7P2) of the third electrode layers 25. For this reason, the third electrode layers 25 are thick and it is thus feasible to suppress the effect of damage due to the irradiation with the laser beam in the multilayer capacitor C1, compared to a multilayer capacitor in which the thicknesses T_(5P2), T_(7P2) of the third electrode layers 25 are smaller than the maximum thicknesses T_(5S1), T_(7S1) of the first electrode layers 21.

Each first electrode layer 21 is a sintered conductor layer containing Cu. The first internal electrodes 11 and the first terminal electrode 5 (first electrode layer 21) are securely kept in contact with each other due to the first internal electrodes 11 being connected to the first electrode layer 21 of t the first terminal electrode 5. The second internal electrodes 13 and the second terminal electrode 7 (first electrode layer 21) are securely kept in contact with each other due to the second internal electrodes 13 being connected to the first electrode layer 21 of the second terminal electrode 7. The first electrode layer 21 may be a sintered conductor layer containing Ni.

Each second electrode layer 23 is an Ni-plated layer. For this reason, the second electrode layer 23 restrains the first electrode layer 21 from being damaged in a process of forming the third electrode layer 25. Therefore, it is feasible to suppress degradation of insulation resistance of the multilayer capacitor C1. The second electrode layer 23 may be an Sn-plated layer.

Each third electrode layer 25 is a Cu-plated layer. For this reason, it is feasible to ensure connectivity between the wiring formed on the substrate and the first and second terminal electrodes 5, 7. The third electrode layer 25 may be an Au-plated layer.

Since the difference between the maximum thickness (T_(5S1)+T_(5P1)+T_(5P2)) and the minimum thickness (T_(5Smin)+T_(5P1)+T_(5P2)) of each electrode portion 5 a or 5 b is smaller than the difference between the maximum thickness (T_(5S2)+T_(5P1)+T_(5P2)) and the minimum thickness (T_(5Smin)+T_(5P1)+T_(5P2)) of the electrode portion 5 c, the electrode portions 5 a, 5 b have a higher degree of flatness than the electrode portion 5 c does. This improves connection reliability between the wiring formed on the substrate and the first terminal electrode 5. Since the difference between the maximum thickness (T_(7S1)+T_(7P1)+T₇₂) and the minimum thickness (T_(7Smin)+T_(7P1)+T_(7P2)) of each electrode portion 7 a or 7 b is smaller than the difference between the maximum thickness (T_(7S2)+T_(7P1)+T_(7P2)) and the minimum thickness (T_(7Smin)+T_(7P1)+T_(7P2)) of the electrode portion 7 c, the electrode portions 7 a, 7 b have a higher degree of flatness than the electrode portion 7 c does. This improves connection reliability between the wiring formed on the substrate and the second terminal electrode 7.

The via holes by laser processing are formed in tapered shape with their diameter decreasing from the surface side of the substrate to the first or second terminal electrode 5, 7 (electrode portion 5 a, 5 b, 7 a, 7 b) side. The farther the distance from the surface of the substrate, the smaller the inside diameter of each via hole. Namely, the farther the distance from the surface of the substrate, the smaller the area of the via conductor formed in each via hole. As the areas of the via conductors become smaller, connection areas between the first and second terminal electrodes 5, 7 and the via conductors also become smaller.

When the electrode portions 5 a, 5 b have the higher degree of flatness than the electrode portion 5 c does, the distances from the surface of the substrate to the electrode portions 5 a, 5 b of the first terminal electrode 5 are approximately constant. Therefore, when a plurality of via conductors are connected to the first terminal electrode 5, the connection areas between each of the via conductors and the first terminal electrode 5 are equivalent. When the electrode portions 7 a, 7 b have the higher degree of flatness than the electrode portion 7 c does, the distances from the surface of the substrate to the electrode portions 7 a, 7 b of the second terminal electrode 7 are approximately constant. Therefore, when a plurality of via conductors are connected to the second terminal electrode 7, the connection areas between each of the via conductors and the second terminal electrode 7 are equivalent. These configurations improve the connection reliability between the via conductors and the first and second terminal electrodes 5, 7.

The thicknesses T_(3B), T_(3C) of the respective outer layer portions 3B, 3C are smaller than the maximum thickness (T_(5S1)+T_(5P1)+T_(5P2)) of each electrode portion 5 a or 5 b and smaller than the maximum thickness (T_(7S1)+T_(7P1)+T_(7P2)) of each electrode portion 7 a or 7 b. For this reason, in the multilayer capacitor C1, it is feasible to achieve further reduction in height, compared to a multilayer capacitor in which the thicknesses T_(3B), T_(3C) are not less than the maximum thicknesses (T_(5S1)+T_(5P1)+T_(5P2), T_(7S1)+T_(7P1)+T_(7P2)) of the electrode portions 5 a, 5 b, 7 a, 7 b.

The maximum thicknesses (T_(5S1)+T_(5P1)+T_(5P2), T_(7S1)+T_(7P1)+T_(7P2)) of the electrode portions 5 a, 5 b, 7 a, 7 b are larger than the thicknesses T_(3B), T₃₀. For this reason, each of the electrode portions 5 a, 5 b, 7 a, 7 b is thick in the multilayer capacitor C1, compared to a multilayer capacitor in which the maximum thicknesses (T_(5S1)+T_(5P1)+T_(5P2), T_(7S1)+T_(7P1)+T_(7P2)) of the electrode portions 5 a, 5 b, 7 a, 7 b are not more than the thicknesses T_(3B), T_(3C). Therefore, it is feasible to suppress the effect of damage due to the irradiation with the laser beam even in the case where the electrode portions 5 a, 5 b, 7 a, 7 b are irradiated with the laser beam.

The length in the first direction D1 of the element body 2 is smaller than the lengths L₅₁, L₇₁. For this reason, it is feasible to achieve further reduction in height of the multilayer capacitor C1. In the multilayer capacitor C1, the areas of the electrode portions 5 a, 5 b, 7 a, 7 b are large and the electrode areas to be connected to the wiring formed on the substrate are large, compared to a multilayer capacitor in which the lengths L₅₁, L₇₁ are smaller than the length in the first direction D1 of the element body 2. For this reason, it is easy to implement connection between the wiring formed on the substrate and the first and second terminal electrodes 5, 7.

The length in the first direction D1 of the element body 2 is smaller than the gap G₁. This configuration also achieves further reduction in height of the multilayer capacitor C1.

The gap G₁ is not more than the lengths L₅₁, L₇₁. In this case, in the multilayer capacitor C1, the areas of the electrode portions 5 a, 5 b, 7 a, 7 b are large and the electrode areas to be connected to the wiring formed on the substrate are large, compared to a multilayer capacitor in which the gap G₁ is larger than the lengths L₅₁, L₇₁. For this reason, it is easy to implement connection between the wiring formed on the substrate and the first and second terminal electrodes 5, 7.

The multilayer capacitor C1, as described below, is placed in a housing portion of a substrate and thereafter the housing portion is filled with a resin, whereby the multilayer capacitor C1 is built into the substrate. When the projections 25 a are formed on the surface of the third electrode layers 25 of the Cu-plated layers, the projections 25 a form unevenness on the surface of the third electrode layers 25. In the configuration wherein the projections 25 a are formed on the third electrode layers 25, the surface areas of the third electrode layers 25 are large and better engagement is achieved between the third electrode layers 25 and the resin due to the unevenness, compared to a configuration without the projections 25 a. Therefore, adhesion between the third electrode layers 25 and resin can be improved when the multilayer capacitor C1 is built into the substrate.

The multilayer capacitor C1, as shown in FIG. 12, is mounted as embedded in a substrate 31. The multilayer capacitor C1 is built into the substrate 31. FIG. 12 is a drawing for explaining a mounted structure of the multilayer capacitor according to the present embodiment.

The substrate 31 is constructed by stacking a plurality of insulating layers 33. The insulating layers 33 are made of an insulating material such as ceramic or resin, and are integrated with each other by adhesion or the like.

The multilayer capacitor C1 is disposed in a housing portion 31 a formed in the substrate 31. The multilayer capacitor C1 is fixed to the substrate 31 by resin 34 filled in the housing portion 31 a. The multilayer capacitor C1 is embedded in the substrate 31. The multilayer capacitor C1 is electrically connected through via conductors 45, 47 to electrodes 35, 37 disposed on the surface of the substrate 31. The first terminal electrode 5 (electrode portion 5 a) is electrically connected through the via conductor 45 to the electrode 35. The second terminal electrode 7 (electrode portion 7 a) is electrically connected through the via conductor 47 to the electrode 37.

The via conductors 45, 47 are formed by growing an electroconductive metal (e.g., Cu or Au or the like) in via holes formed in the substrate 31. The growth of the electroconductive metal is realized, for example, by electroless plating. The via holes are formed to reach the electrode portions 5 a, 7 a of the first and second terminal electrodes 5, 7 of the multilayer capacitor C1 from the surface side of the substrate 31. The via holes are formed, for example, by laser processing.

The first and second terminal electrodes 5, 7 include their respective sufficient connection areas with the via conductors 45, 47 in the flat regions of the electrode portions 5 a, 7 a, For this reason, the first and second terminal electrodes 5, 7 (electrode portions 5 a, 7 a) can be certainly connected to the via conductors 45, 47.

In the multilayer capacitor C1, the electrode portions 5 a, 7 a include the third electrode layers 25 as plated layers. Therefore, the electrode portions 5 a, 7 a can be securely connected to the via conductors 45, 47 formed in the via holes. When the via conductors 45, 47 are formed by plating, the via conductors 45, 47 are more securely connected to the electrode portions 5 a, 7 a.

Next, a configuration of a multilayer capacitor C2 according to a modification example of the foregoing embodiment will be described with reference to FIGS. 13 to 16. FIG. 13 is a perspective view showing the multilayer capacitor according to the present modification example. FIGS. 14 to 16 are drawings for explaining cross-sectional configurations of the multilayer capacitor according to the present modification example.

The multilayer capacitor C2 includes the element body 2, the first terminal electrode 5 and second terminal electrode 7, the plurality of first internal electrodes 11, and the plurality of second internal electrodes 13.

The length in the first direction D1 of the element body 2, i.e., the length in the height direction of the element body 2 is smaller in the multilayer capacitor C2 than that in the multilayer capacitor C1. In the present modification example, the thicknesses T_(3B), T_(3C) of the respective outer layer portions 3B, 3C are smaller than the thicknesses T_(5P2), T_(7P2) of the third electrode layers 25. For this reason, the present modification example can achieve further reduction in height of the multilayer capacitor C2.

In the multilayer capacitor C2, just as in the multilayer capacitor C1, the maximum thicknesses T_(5S1), T_(7S1) of the first electrode layers 21 are also larger than the thicknesses T_(5P1), T_(7P1) of the second electrode layers 23 in the electrode portions 5 a, 5 b, 7 a, 7 b. For this reason, it is feasible to reduce the stress occurring in the process of forming the second electrode layers 23 on the first electrode layers 21. In the multilayer capacitor C2, the maximum thicknesses T_(5S1), T_(7S1) of the first electrode layers 21 are also not more than the thicknesses T_(5P2), T_(7P2) of the third electrode layers 25 in the electrode portions 5 a, 5 b, 7 a, 7 b. For this reason, the thicknesses T_(5P2), T_(7P2) of the third electrode layers 25 are larger than the maximum thicknesses T_(5S1), T_(7S1) of the first electrode layers 21 and it is thus feasible to suppress the effect of damage due to the irradiation with the laser beam.

The embodiment of the present invention has been described above, but it should be noted that the present invention is not always limited only to the above-described embodiment but can be modified in many ways without departing from the spirit and scope of the invention.

The first terminal electrode 5 does not always have to include the electrode portion 5 a and the electrode portion 5 b. It is sufficient that the first terminal electrode 5 includes at least either of the electrode portion 5 a and the electrode portion 5 b as an electrode portion to be connected to the wiring formed on the substrate. The second terminal electrode 7 does not always have to include the electrode portion 7 a and the electrode portion 7 b. It is sufficient that the second terminal electrode 7 includes at least either of the electrode portion 7 a and the electrode portion 7 b as an electrode portion to be connected to the wiring formed on the substrate.

The first terminal electrode 5 does not have to include the electrode portions 5 d. The first terminal electrode 5 may be formed on the three surfaces 2 a, 2 b, and 2 c. The second terminal electrode 7 does not have to include the electrode portions 7 d. The first terminal electrode 7 may be formed on the three surfaces 2 a, 2 b, and 2 d.

FIG. 12 shows the configuration wherein the multilayer capacitor C1 is embedded in the substrate 31, but the multilayer capacitor C2 may be mounted as embedded in the substrate 31. 

What is claimed is:
 1. A multilayer capacitor comprising: an element body of a rectangular parallelepiped shape, the element body including a pair of principal surfaces opposing each other in a first direction, a pair of first side surfaces opposing each other in a second direction perpendicular to the first direction, and a pair of second side surfaces opposing each other in a third direction perpendicular to the first and second directions; a plurality of first internal electrodes and second internal electrodes alternately disposed in the element body to oppose each other in the first direction; a first terminal electrode including a first electrode portion disposed on one of the pair of principal surfaces and a second electrode portion disposed on one of the first side surfaces, the second electrode portion being connected to the plurality of first internal electrodes; and a second terminal electrode including a third electrode portion disposed on the one of the pair of principal surfaces and a fourth electrode portion disposed on an other of the first side surfaces, the third electrode portion being separated from the first electrode portion in the second direction on the one of the pair of principal surfaces, the fourth electrode portion being connected to the plurality of second internal electrodes, wherein the element body includes an inner layer portion and a pair of outer layer portions, the inner layer portion being located between the pair of outer layer portions in the first direction, the plurality of first internal electrodes and the plurality of second internal electrodes being located in the inner layer portion, wherein a length in the first direction of the element body is smaller than a length in the second direction of the element body and smaller than a length in the third direction of the element body, wherein each of the first terminal electrode and the second terminal electrode includes a sintered conductor layer formed on the element body, a first plated layer formed on the sintered conductor layer, and a second plated layer formed on the first plated layer, wherein in each of the first electrode portion and the third electrode portion, a maximum thickness of the sintered conductor layer is larger than a thickness of the first plated layer and not more than a thickness of the second plated layer, wherein a difference between a maximum thickness and a minimum thickness of the first electrode portion is smaller than a difference between a maximum thickness and a minimum thickness of the second electrode portion, and wherein a difference between a maximum thickness and a minimum thickness of the third electrode portion is smaller than a difference between a maximum thickness and a minimum thickness of the fourth electrode portion.
 2. The multilayer capacitor according to claim 1, wherein the sintered conductor layer contains Cu or Ni.
 3. The multilayer capacitor according to claim 1, wherein the first plated layer contains Ni or Sn.
 4. The multilayer capacitor according to claim 1, wherein the second plated layer contains Cu or Au.
 5. The multilayer capacitor according to claim 1, wherein thicknesses of the respective outer layer portions are smaller than a maximum thickness of the first electrode portion and smaller than a maximum thickness of the third electrode portion.
 6. The multilayer capacitor according to claim 1, wherein the length in the first direction of the element body is smaller than a length in the second direction of the first electrode portion and smaller than a length in the second direction of the third electrode portion.
 7. The multilayer capacitor according to claim 1, wherein the length in the first direction of the element body is smaller than a gap between the first electrode portion and the third electrode portion in the second direction.
 8. The multilayer capacitor according to claim 1, wherein: the length of the element body in the second direction is greater than the length of the element body in the third direction; and a gap between the first electrode portion and the third electrode portion in the second direction is not more than a length in the second direction of the first electrode portion and not more than a length in the second direction of the third electrode portion.
 9. The multilayer capacitor according to claim 1, wherein thicknesses of the respective outer layer portions are smaller than the thickness of the second plated layer.
 10. The multilayer capacitor according to claim 1, wherein the second plated layer is a Cu-plated layer, and wherein projections being made of Cu are formed on a surface of the Cu-plated layer. 